The goal of Phase I of this clinical research study is to find the
highest tolerable dose of ONC201 that can be given to patients with
relapsed or refractory AML, ALL, or MDS. The goal of Phase II of this
study is to learn if the dose of ONC201 found in Phase I can help to
control the disease. The safety of the study drug will be studied in
both phases of this study. This is the first study using ONC201 in humans.